Rock Rapids, located in the geographical center of Lyon County, was chosen as the first county seat. A successful vote at a general election led to the approval of a $15,000 contract for a courthouse in April, 1874. A two-story frame building was finished in 1875.

The second courthouse was built in 1916 and remains in nearly its original condition. The outer walls are made of cut Bedford stone lined with brick. The building measures approximately 110 feet by 71 feet and is 52 feet high. A full-size cast stone lion guards the main entryway and Italian marble lines the corridors leading to a rotunda. The building cost $109,695.13.